While it had been previously proposed by scientists that genes were contained in DNA, the experiment done by these two geneticists provided proof. Their results showed that DNA is the genetic material of the virus called T2 that infects the bacterium E.coli. Originally, scientists believed proteins were the material that allowed bacteriophages to replicate. They thought this because there are so many different types of amino acids that make up the proteins compared to the four nucleic acids that made up DNA. They suspected that replication was far too complicated a process for a molecule as basic as DNA. However, through this experiment, it was proved that proteins weren’t the genetic material: it was DNA.
Organism Utilized for Experimentation:
== E. Coli (Escherichia coli), Phage (bacteriophage)
== The Experiment: The purpose of the experiment was to identify how the bacteriophage called T2 could make the host cell reproduce phages. The scientists used phages and E. coli cells to figure out which part of the phage caused reproduction, DNA or proteins. This could be found simply by learning what the phage transferred to the healthy cell. Hershey and Chase cultivated two batches of T2 with E.coli, one with radioactive protein (containing sulfur) and the other with radioactive DNA (containing phosphorous). These were then allowed to infect bacteria samples, and were placed in a centrifuge to separate the cells and the remains of the phages. In the sample with the radioactive protein, the cells did not contain radioactivity. On the other hand, the cells in the sample containing the radioactive DNA was found to have radioactivity. This allowed the scientists to conclude that DNA carried the genetic information rather than proteins. Animation of the Experiment
Significance of Research:The significance of the experiment is that the results showed that DNA, not protein, is what carries the genetic information to make a new generation phage. When this was established the focus of DNA and genetic research was changed because scientists now knew what was behind replication and reproduction.
Bibliography:
Campbell, Neil A., Jane B. Reece, Lawrence G. Mitchell, and Martha R. Taylor. Biology Concepts & Connections. 4th ed. San Francisco: Benjamin Cummings, 2003. Print.
Campbell, Neil A.. "Molecular Biology of the GEne." Biology: concepts & connections. 4th ed. San Francisco: Benjamin Cummings, 2003. 184, 185. Print.
"The Hershey and Chase Experiments." RCN D.C. Metro | High-Speed Internet, Digital Cable TV & Phone Service Provider. N.p., 2 Apr. 2008. Web. 14 Apr. 2011. <http://users.rcn.com/jkimball.ma
Carter, J. Stein. "DNA Structure and Function." Biology at Clermont College - University of Cincinnati. Scilinks, 11 Feb. 2004. Web. 14 Apr. 2011. <http://biology.clc.uc.edu/courses
Hershey and Chase
Contribution to Genetics:
While it had been previously proposed by scientists that genes were contained in DNA, the experiment done by these two geneticists provided proof. Their results showed that DNA is the genetic material of the virus called T2 that infects the bacterium E.coli. Originally, scientists believed proteins were the material that allowed bacteriophages to replicate. They thought this because there are so many different types of amino acids that make up the proteins compared to the four nucleic acids that made up DNA. They suspected that replication was far too complicated a process for a molecule as basic as DNA. However, through this experiment, it was proved that proteins weren’t the genetic material: it was DNA.Organism Utilized for Experimentation:
==E. Coli (Escherichia coli), Phage (bacteriophage)
The Experiment:
The purpose of the experiment was to identify how the bacteriophage called T2 could make the host cell reproduce phages. The scientists used phages and E. coli cells to figure out which part of the phage caused reproduction, DNA or proteins. This could be found simply by learning what the phage transferred to the healthy cell.
Hershey and Chase cultivated two batches of T2 with E.coli, one with radioactive protein (containing sulfur) and the other with radioactive DNA (containing phosphorous). These were then allowed to infect bacteria samples, and were placed in a centrifuge to separate the cells and the remains of the phages. In the sample with the radioactive protein, the cells did not contain radioactivity. On the other hand, the cells in the sample containing the radioactive DNA was found to have radioactivity. This allowed the scientists to conclude that DNA carried the genetic information rather than proteins.
Animation of the Experiment
Significance of Research:The significance of the experiment is that the results showed that DNA, not protein, is what carries the genetic information to make a new generation phage. When this was established the focus of DNA and genetic research was changed because scientists now knew what was behind replication and reproduction.
- Campbell, Neil A., Jane B. Reece, Lawrence G. Mitchell, and Martha R. Taylor. Biology Concepts & Connections. 4th ed. San Francisco: Benjamin Cummings, 2003. Print.
- "Hershey and Chase Experiment." Hershey and Chase Experiment. McGraw Hill Companies Inc, 2011. Web. 12 Apr. 2011. <http://glencoe.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/hershey_and_chase_experiment.html>.
- Campbell, Neil A.. "Molecular Biology of the GEne." Biology: concepts & connections. 4th ed. San Francisco: Benjamin Cummings, 2003. 184, 185. Print.
- "The Hershey and Chase Experiments." RCN D.C. Metro | High-Speed Internet, Digital Cable TV & Phone Service Provider. N.p., 2 Apr. 2008. Web. 14 Apr. 2011. <http://users.rcn.com/jkimball.ma
- Carter, J. Stein. "DNA Structure and Function." Biology at Clermont College - University of Cincinnati. Scilinks, 11 Feb. 2004. Web. 14 Apr. 2011. <http://biology.clc.uc.edu/courses
Alev, Emily, Amy, Jared,Cory